ActionScript APIs specific to mobile AIR applications

The following APIs are available only in AIR applications on mobile devices. They are not currently functional in Flash Player or desktop versions of AIR.

Screen orientation API

The screen orientation API lets you work with the orientation of the stage and the iPhone:

Stage.autoOrients— Whether the application is set to have the stage automatically reorient when the device is rotated. This property is set to true when the Auto Orientation option is selected in the Flash Professional CS5 iPhone Settings dialog box. (You can also set the autoOrients element to true in the application descriptor file.) See iPhone application settings. You can cancel the automatic reorientation by adding anorientationChanging event listener for the Stage object. Calling the preventDefault() method of this event object cancels the automatic reorientation.

When using auto-orientation, for best results set the align property of the Stage to the following:

Stage.deviceOrientation—The physical orientation of the device. The StageOrientation class defines values for this property.

Stage.orientation—The current orientation of the stage. The StageOrientation class defines values for this property.

Stage.supportsOrientationChange—Set to true on the iPhone, and false in an AIR application.

Stage.setOrientation()—Sets the orientation of the stage. This method has one parameter, which is a string defining the new stage orientation. The constants in the StageOrientation class define possible values for the parameter.

StageOrientation—Defines stage orientation values. For example, StageOrientation.ROTATED_RIGHT indicates a stage that is rotated right relative to the default orientation of the device.

StageOrientationEvent—Defines events that the Stage dispatches when the orientation of the screen changes. This event occurs when the user rotates the iPhone. There are two types of events. The Stage dispatches theorientationChanging event as the device is being rotated. To prevent the stage from reorienting, call the preventDefault() method of the orientationChanging event object. The Stage dispatches theorientationChange event once the stage reorientation is complete.

Currently, the screen orientation API is only useful in AIR applications on mobile devices. If a mobile AIR application and a desktop AIR application share source code, use the Stage.supportsOrientationChange property to check if the API is supported.

The following example shows how to respond to the user rotating the device:

In this example, in the case of different stage orientations, there are comments instead of functional code.

You can change the orientation of the stage by calling the setOrientation() method of the Stage object. Setting the orientation is an asynchronous operation. You can check when the orientation is complete by listening for theorientationChange event. The following code shows how to set the stage to the right-hand orientation:

As the Stage rotates it resizes, and the Stage object dispatches a resize event. You can resize and reposition display objects on the Stage in response to the resize event.

NativeApplication.systemIdleMode and SystemIdleMode

The NativeApplication.systemIdleMode property lets you prevent the iPhone from going into idle mode. By default, an iPhone goes into idle mode if there is no touch screen interaction for some period. Idle mode can cause the screen to dim. It can also cause the iPhone to go into lock mode. This property can be set to one of two values:

SystemIdleMode.KEEP_AWAKE—The application attempts to prevent the iPhone from going into idle mode.

This functionality is only supported on mobile devices. It is not supported in AIR applications running on desktop operating systems. In an application running on the desktop, setting the NativeApplication.systemIdleModeproperty has no effect.

CameraRoll

The CameraRoll class lets you add an image to the iPhone camera roll. The addBitmapData() method adds an image to the iPhone camera roll. The method has one parameter, bitmapData. This parameter is the BitmapData object containing the image to add to the camera roll.

CameraRoll functionality is only supported on mobile devices. It is not supported in AIR applications running on desktop operating systems. To check at runtime whether your application supports the CamerRoll functionality, check the static CameraRoll.supportsAddBitmapData property.

After you call the addBitmapData() method, the CameraRoll object dispatches one of two events:

complete—The operation completed successfully.

error—There was an error. For example, perhaps there is not enough free space on the iPhone to store the image.

The following code adds an image of the stage (a screen capture) to the camera roll:

DisplayObject.cacheAsBitmapMatrix

The cacheAsBitmapMatrix property is a Matrix object that defines how a display object is rendered when cacheAsBitmap is set to true. The application uses this matrix as a transformation matrix when rendering the bitmap version of the display object.

With cacheAsBitmapMatrix set, the application retains a cached bitmap image rendered using that matrix, instead of the display matrix. (The display matrix is the value of the transform.concatenatedMatrix of the display object.) If this matrix does not match the display matrix, the bitmap is scaled and rotated as necessary.

A display object with cacheAsBitmapMatrix set is only rerendered when the value of cacheAsBitmapMatrix changes. The bitmap is scaled or rotated as appropriate to conform to the display matrix.

Both CPU- and GPU-based rendering benefit from the use of the cacheAsBitmapMatrix property, although GPU rendering typically benefits more.

Note: To use the hardware acceleration, set the Rendering to GPU in the General tab of the iPhone Settings dialog box in Flash Professional CS5. (Or set the renderMode property to gpu in the application descriptor file.)

For example, the following code uses an untransformed bitmap representation of the display object:

Usually, the identity matrix (new Matrix()) or transform.concatenatedMatrix suffices. However, you can use another matrix, such as a scaled-down matrix, to upload a different bitmap to the GPU. For example, the following example applies a cacheAsBitmapMatrix matrix that is scaled by 0.5 on the x- and y-axes. The bitmap object that the GPU uses is smaller, however the GPU adjusts its size to match the transform.matrix property of the display object.:

Generally, choose a matrix that transforms the display object to the size that it will appear in the application. For example, if your application displays the bitmap version of the sprite scaled down by a half, use a matrix that scales down by a half. If your application will display the sprite larger than its current dimensions, use a matrix that scales up by that factor.

There is a practical limit to the size of display objects for which the cacheAsBitmapMatrix property is set. The limit is 1020 by 1020 pixels. There is a practical limit for the total number of pixels for all display objects for which the cacheAsBitmapMatrix property is set. That limit is about four million pixels.

There are many considerations when using cacheAsBitmapMatrix and hardware acceleration. It is important to know which display objects should have that property set, and which ones should not. For important information on using this property, see Hardware acceleration.

You can use the GPU rendering diagnostics feature to diagnose GPU usage in debug builds of your application. For more information, see Debugging an iPhone application.

Networking notes

Using the following URL schemes with the nativigateToURL() function causes a document to open in an external application:

An iPhone application may rely on installed self-signed root certificates for server authentication during a secure transaction, such as an https request. A server should send not just the leaf certificate but also all intermediate certificates chaining to the root certificate.